A Descriptive Comparison of Green Bond Versus Conventional Loan Financing for a 10 MWp Solar Farm in Central Vietnam: Financial and Environmental Outcomes

This descriptive case study compares the financial and environmental performance of a 10 MWp grid-connected solar photovoltaic farm in Quang Nam province, Vietnam, under two financing scenarios: a certified green bond (5.5% interest rate) and a conventional commercial loan (8.5% interest rate). Technical and financial data were obtained from three operational reference projects in the same region. Key descriptive indicators included capital expenditure composition, annual electricity generation, interest payments, payback period, and avoided carbon dioxide emissions. Results showed that the green bond reduced total interest payments by 1.52 million United States dollars over seven years, equivalent to 17.8% of total project cost, despite an upfront certification fee of 86,880 United States dollars. The equity payback period shortened from 5.8 years under the conventional loan to 4.2 years under the green bond, a reduction of 27.6%. The solar farm is estimated to generate 290,432 megawatt-hours of clean electricity over 20 years, avoiding 152,742 metric tons of carbon dioxide emissions. These descriptive findings suggest that green bond financing can substantially improve both financial viability and environmental outcomes for small-scale solar projects in emerging markets. The study recommends policy support for green bond guarantee schemes and standardized certification processes for projects between 5 and 30 megawatts.